Literally "trout" in Spanish, it is also Spanish slang for "alert", or "vigilant". It was a combined with the word "Salvadorian" to form "Salvatrucha", as in Mara Salvatrucha, or the street gang MS13.
It is used as a warning, for example, similar to "heads-up".
TikTok Farlands is a term to refer to videos that you see after scrolling for a long time. These videos can potentially be disturbing, or weird. Said videos can also have low likes, or low comments.